NAME

SYNOPSIS

DESCRIPTION

The tcdrain() function shall block until all output written to the object referred to by fildes is transmitted.
The fildes argument is an open file descriptor associated with a terminal.

Any attempts to use tcdrain() from a process which is a member of a background process group on a fildes
associated with its controlling terminal, shall cause the process group to be sent a SIGTTOU signal. If the calling thread is
blocking SIGTTOU signals or the process is ignoring SIGTTOU signals, the process shall be allowed to perform the operation, and no
signal is sent.

RETURN VALUE

Upon successful completion, 0 shall be returned. Otherwise, -1 shall be returned and errno set to indicate the error.

ERRORS

The tcdrain() function shall fail if:

[EBADF]

The fildes argument is not a valid file descriptor.

[EINTR]

A signal interrupted tcdrain().

[EIO]

The process group of the writing process is orphaned, the calling thread is not blocking SIGTTOU, and the process is not
ignoring SIGTTOU.